A man linked to a gun used to kill a university police officer days after the Boston Marathon bombings told police he smoked marijuana every day because, in his words, “my best friend was the bomber,” according to court documents.

The universe was born almost 14 billion years ago, exploding into existence in an event called the Big Bang. Now researchers say they’ve spotted evidence that a split-second later, the expansion of the cosmos began with a powerful jump-start.